Aeronautic chart



Sept. 2 1924; 1,507,191

S. B. LADD AERONAUTIC (KART Filed llarch 6. 1922 0 o o o 0 o o o o o o o o o o 6 A :a E F Kansas v C O D G H T Oklahoma 3 O J M N o I K o L O P Texas Patented Sept. 2, 1924.

STORY B. LADD, OF WASHINGTON, DISTRICT OF COLUMBIA.

AERONAUTIC CHART.

Application filed March 6, 1922.

1 0 all whom it may concern:

Be it known that I, STORY B. LADD, a citizen of the United States, residing at Washington, in the District of Co1umbia,have invented certain new and useful Improvements in Aeronautic Charts, of which the following is a specification.

This invention relates to an aeronautic chart system adapted to function in aiding the aviator or observer to lay his course direct for the objective point, also to make it possible for him, enroute, to check and correct his course for airdrift.

The underlying principle of the invention or chart is the subdivision of the continental areas into blocks, and the installation of markers at the intersection of block lines which, by reason of their shape, contour, or distinguishing features, as viewed from the aeroplane, or overhead, will indicate to the aviator or observer the geographic position ofthe marker.

It is not proposed to post the entire country, nor any portion thereof, by the installation of markers at all points, but to provide a system which can'be added to or differentiated as the growth of air-travel requires, and whenever or wherever a marker is installed, whether under national or State auspices, by aero-clubs, chambers of commerce, or other organization, it will be in harmony with the general plan, and become a part of the continental system.

The blocks will be spherical quadrilaterals, laid out on lines of latitude and longitude, the term as here used referring to an area bounded on the east and west by north and south lines, and on the north and south by east and west lines; by meridians of longitude and parallels of latitude, respectively. The term marker as used herein refers to a device or structure, preferably erected so as to stand above other objects in the neighborhood and be distinguishable at a distance.

It is important that the system, in its growth and development, be continental in its scope, without breaks at national or State boundaries, and that the character or ,indicia of all markers, Wherever installed, shall be alike in markings and significance, and suggestive of the same import to the aviator. In this presentation it is described as applicable to a world system.

Eight degrees of Ion itude and latitude represent a major bloc these being sub- Serial No. 541,549.

divided into quarter sections, and each quarter section into quarter blocks, giving, as a result, 16 quadrilaterals, 2 by 52, these being referred to as intermediate blocks. These intermediate blocks are in like manner subdivided into quadrilaterals of 24 by 24, making 25 subdivisions. These are the minor-block units, and each marker that is installed represents a minor-block.

Each major block being of 8 standard for all countries, those of the equatorial belt will be approximately 550 miles square with intermediates (2X2) of 138 miles square, and minor blocks (24LX24) of 27.6 miles. Going north and south from the equator, the distances along meridianal lines will be constant, with the distances along parallels of latitude gradually diminishing. At the 40th parallel, the east and west dimensions for the major blocks will be approximately 428 miles; for intermediates, 107 miles; and for a minor block, 21.4 miles. At the th parallel of latitude, these distances will be approximately 360 miles; 90 miles; and 18 miles, respectively; and at 280 miles, miles, and 14 miles respectively.

Fig. 1 is a diagrammatic view showing a section of continental area divided into blocks in accordance with the present in vention;

Fig. 2 is an enlarged diagrammatic view illustrating division into minor blocks; and

Fig. 3 is a perspective view showing a marker embodying the present invention; and

Fig. 4 is a series of top plan views of markers embodying the present invention.

For purposes of identification, the intermediate blocks are lettered A to P, beginning at the northwest corner of a major block and in quarter section groups, the letters A, B, C, and D, as in diagram Figure 1, indicating the four intermediate blocks of the northwest quarter section; E, F, G, and H, those of the northeast quarter section; I, J, K, and L, the southwest quarter section; and M, N, O, and P, the southeast.

The major blocks'are designated by the longitude and latitude of the northwest corner of the block, and as all major blocks are 8 in dimensions these numbers are always multiples of 8. Thus 1O l48 defines or identifies a block bounded by meridians 98 and l0t (in the western hemisphere) and by parallels of latitude 40 'tive feature of amarker that identifies the inand 48 (in the northern hemisphere) and 104 32 identifies the ma or block covering southern Texas and a portion of Mexico.

If there be any questionas to the quarter of west corner of which is 104 west longitude,

and 48 north latitude. I

The minor blocks are designated 1 to 525 beginning at the northwest corner of the intermediate block. In designating a minor ,block, the number follows the intermediate block letter, thus, lOa't-tSClO identifies a specific location of a minor block (which may or may nothave been installed), in block ].0-Ll48(l' The markers are platform structures, as indicated in the diagrammatic Figures 8 and 4, carried by skeleton towers, high enoujg'lito clear or be observable above surrounding objects, and, in forest and timbered districts, to show above the trees; and in open country they may be of an elevation sufficient to be out. of the way of cattle and drifting snows.

In mountainous or broken country where the true location of a marker comes in a gorge, or where it would not be visible fro-1n a distance, it will be located at the nearest available point, the offset showing on the charts. v

The contour of the platform is the distinctermediate block in which it is located, It is desirable that the distinctive types be as few and simple as possible, those recommended being circular, square, triangular, and a trefoil. All markers within an intermediate block are to be of the same contour,

and the shape of the platform "as viewed or observed from above readily identifies the intermediate block, andthe four shapes I suffice for the fourintermediates that form a quarter section of a ma or block.

v,It is necessary that the visibility of the markers be preserved under snow cond1t1ons when the ground and 'the platforms are white with snow. For this'purpose the platforms are made with a skirt or flange around the outer rim or edge sloping outward. at asteep angle and preferably painted black. From above this will appear to the in a prior presentation ofthe' project, the 7 markers were to be provided with anarm projection to the northwest, the i'iortheast, the southwesti'or the southeast, as the case might be. An arm projecting" out from the rimof a marker will detract from the dis 30 tinctivcness of thecontour andlbe confusing to the observer, and moreover he might be in doubt as to the compass-direction in which the arm was pointing.- It'is therefore proposed that the quarter section be indi cated by one or more discs, separate and detach-ed from the marker platform, but car- 'ried by the platform-structure on a level with the platform.

teri'al. They will be far enough removed from the platform so that under snow conditions the space between a disc and the platform will not be bridged by the snow and The position of these discs with respect to the platform is immathe outlineof the platform be broken. One

disc may signify thc'first or northwest qua-rterof the major block two discs the second or northeast quarter, three the northwest, quarter, and four the southeast quarter; or the absenceof any disc may signify the first quarter-section, and one, two or three discs the other quarter-sections.

The combinatlon of the four contour out linings and the discs provides for thercady identification of any one ofthe 16 intermediate blocks without recourse, on the part ofthe observer, to compass-directions. '1

With respect to the major-blocks} which represent areas of 200,000 "to 300,000square miles, it is assumed that no marker feature is necessary. An aviator will know his'pos'ition as between eastern Massachusetts or Ohio, central Illinois or southern Alabama, the'north of France j or Spain. Vith this knowledge of the marker-shape and the 1 number of accompanying discs," which will appear as dots or spots contiguous to the platform, he at once knowshis position within 2 degrees. J The minor-block units as indicated in Figure 2 are indicated by" numbers, from 1 to 25, 'showingin the centerof the markers. The numbers are placed to bereadf'rom the south and appear separate and detachedfrom the surrounding platform in a central open field. The space between the number and the edge of the surrounding platform will be su'fiicient, in'norther'n districts ,-to bare the formationof a snow bridge. To-main tain the ready visibility-of the numbers under snow-conditions, they are preferably of precipitately sloped steel or metal strips painted black. Though in winter, in some districts, a marker may carry a heavy snowblanket, there will be open space around the designating number and the lines will be sufiiciently exposed to be readily decipherable. An aviator may not be able to read the number from a considerable elevation, but, if knowledge of the intermediate block from the marker contour is not sufficient, he can descend low enough to decipher the number.

A marker located Within the confines of a minor block. for example in proximity to a landing field, will show the features called for by that minor block with the addition of an inside ring around the legend or number and a narrow annular space between the ring and the platform. This device will signify that the marker is within the area of the block, the position of the same being shown in the chart for that district.

At the frontier crossing of a posted route the boundary line may be marked by a split platform of the contour called for by the intermediate block but without a number or character, the platform being divided by a central gap conforming in direction to the boundary line.

As installations are made from time to time, the locations will be published as items of general news and the aviators will mark the locations on their charts. This publication will call simply for the longitude and latitude designation of the maior-block, the intermediate block-letter, and the minor block-number. In the case of a marker that is ofl the true location, its position will be given by coordinates with respect to the block-corner; as, for example, when because of the topography of the country 104-40 D 8 is erected 2 miles north and 3 miles east of the northwest-corner of said block.

If a continental route is posted on an unbroken east and west, or north and south line. there will be a duplication of the markers in the major-blocks traversed. For example, if a due east and west transcontinental line he posted from Georgia to- California, the series of markers in blocks 80l0, 8840, 964.-0, lO :l 4'0, 11240, 120 LO" and 12840 will be duplications. This can be avoided, in laying out the line, by offsets between major blocks. If at the junction of 80- 40 and 88-40" the line be sidestepped to the next tier of minor blocks, say to the north, it will strike a different series of marker numbers; then crossing to 964l0 let there be another offset and likewise with each successive block. There will then be no duplicate marker at any point on the entire line. The same course can be followed with respect to north or south posted lines.

A cordon of markers surrounding an industrial district will give an aviator his bearings from whatever direction he approaches. Knowing the latitude and longitude of a point within a district, the block locations and the proper contour, quartersection designation, and numbers are readily determinable.

For night service on a route where there is regular travel the markers may be equipped with lights, under radio control, so that an aircraft, with wireless-controlequipment, may, at will, cut in the lights within range, and lights will be on only as needed.

I claim:

An aeronautic chart system, including a marker-instrumentality contoured to have an open central field and adapted to function as an elevated platform, said platform having: a distinguishing element arranged and observable within said central open field for indicating a unit of the system.

In witness whereof I hereunto set my hand.

STORY B. LADD. 

